1. Field of the Invention
The present invention relates generally to switches. In particular, the present invention relates to a switch apparatus used as, for example, a power window switch for an automobile.
2. Description of the Related Art
FIGS. 10 and 11 illustrate a conventional switch apparatus as disclosed, for example, in Japanese Patent Laid-Open No. 9-167543. FIG. 10(a) is an exploded perspective view of the conventional switch apparatus with some parts omitted. FIG. 10(b) is a side view. FIG. 10(c) is a cross-sectional view with some parts omitted, taken along line SA—SA of FIG. 10(b).
As shown in FIG. 10, a switch apparatus 201 has a knob-mounting portion 205 formed on the top of a case 203. An operating knob 209 is supported so that it rocks back and forth on a support pin 207 of the knob-mounting portion 205. The operating knob 209 has a knob-leg 211 that is inserted into the case 203. The lower end of the knob-leg 211 engages an engagement portion 215 of the slide switch 213 disposed in the case 203. A light source 217 is provided in the case 203 as shown, for example, in FIG. 10(c). The operating knob 209 has an indicator through which the light of the light source 217 transmits, so that the indicator can be visually recognized easily even at night.
For example, FIG. 11 illustrates the relation between the slide switch 213 and the knob-leg 211. FIG. 11(a) is an exploded perspective view of a pertinent portion, illustrating the relation between the slide switch and the knob-leg when they engage each other. FIG. 11(b) is a side view of the pertinent portion, illustrating the slide switch and the knob-leg. FIG. 11(c) is a front view of the pertinent portion, illustrating the slide switch and the knob-leg.
The knob-leg 211 is provided with a bifurcation 219 for engaging a later described element. The slide switch 213 has an operating boss 221 that is supported by the case 203 and serves as an engagement portion with which the bifurcation 219 of the knob-leg 211 is engaged.
When the operating knob 209 is operated in a rocking manner, the operating boss 221 receives a force from the bifurcation 219 through the rocking movement, the force being oriented in one of directions shown by arrow A in FIG. 11(b). Thus, the operating boss 221 operatively slides in one of directions shown by arrow B in FIG. 11(a) so that the slide switch 213 is switched. Thus, the operation of the operating knob 209 in a rocking manner allows easy switching of the slide switch 213 through the knob-leg 211.
However, with the aforementioned construction, there is a possibility of the knob-leg 211 disengaging from the operating boss 221 as shown in FIG. 11(c) due to warning of the knob-leg 211, so that the slide switch 213 cannot be properly operated.
To solve this problem, the rigidity of the knob-leg 211 may be increased by increasing the thickness of the knob-leg 211, thereby restricting the warning of the knob-leg 211 to prevent the knob-leg 211 from disengaging from the operating boss 221.
When the light source 217 disposed in the case 203 illuminates the operating knob 209 as shown in FIG. 10(c), an increased thickness of the knob-leg 211 may block the light emitted from the light source 217. Therefore, there is a possibility of the operating knob 209 not being illuminated sufficiently.